9 



When they are full grown they remain in the fruit until there 

 comes a rain, which causes a rapid decay and a cracking open 

 of the infested fruit. Through the openings so made they 

 emerge and drop to the ground." * They then enter the soil 

 an inch or two where somewhat later they make oval cocoons 

 of silk mixed with particles of earth or sand : in these cocoons 

 they apparently remain unchanged until the following spring 

 when they become pupae and shortly afterwards again change 

 to adult flies. 



These midges appear to have decided preferences among va- 

 rieties of pears, the Lawrence being the favorite. 



Remedies. — The only stage at which this insect is liable to 

 injury without detriment to the trees is when the larvae are in 

 the ground. Professor J. B. Smith of New Jersey has found 

 that they then can be destroyed to advantage by the application 

 of kainit applied about the middle of June to the ground 

 beneath the trees at the rate of i,ooo pounds to the acre. This 

 is dissolved by the soil moisture and causes the death of the 

 naked midge larvae. In case an orchard is generally infested 

 Professor Smith recommends the following practice : " Cultivate 

 as usual, or, if the orchard is in grass or clover, plow under 

 after June 15th, as soon as maybe. Top-dress with kainit, 

 1,000 pounds to the acre, to benefit trees as well as to kill in- 

 sects. As soon as proper, say early in August, sow crimson 

 clover. This will use up the potash not required by the fruit 

 trees, and will store nitrogen, as well as occupy the ground. 

 Early in the following spring turn this sod under as deeply as 

 may be proper. It should be done before the pear buds are 

 developed, in order to head off and destroy any midges then in 

 the pupa state near the surface of the soil." 



The Pear-tree Psylla 



Psylla pyricola 



This is an extremely minute insect, which during recent years 

 has done great damage to pear orchards in several eastern 



* J. B. Smith. 



